1. Field of the Invention
The present invention relates to the means for applying forces to brushes for cleaning underwater surfaces and particularly to brushes that incorporate hydrodynamic planes for increasing contact pressure against a surface being cleaned by motion of an abrasive cleaning device.
2. Prior Art
Periodically, it becomes necessary to clean the walls of swimming pools from accumulated foreign matter such as algae, dirt and scum such as body oil or sun screen. In order to clean the walls of such accumulations, the wall surfaces must be periodically and frequently cleaned by manual scrubbing of the surface with a stiff bristled brush. Long poles are attached to a brush to enable an operator to extend the brush to the bottom of the pool walls, typically 10-15 feet into the typical residential pool. To clean underwater surfaces, a substantial physical force must be exerted since the operator must manipulate the brush by moving the pole about. The deeper the brush is submerged, the more difficult it is for the operator to manipulate the cleaning device. In addition, a brush must be forced against the surface of a pool wall in order to clean the wall.
Brushing vertical walls is particularly difficult because the operator must stand at the edge of the pool and continually force the brush against the pool wall. The difficulty is greatly compounded because of the precarious nature of standing at the edge of a pool when cleaning.
Prior art has addressed this need by suggesting the use of planes or foils attached to a brush or pole for exerting force against the brush as it is moved through the water in the pool. The following is a list of relevant patents issued in the last twenty years.
NameU.S. Pat. No.Date1.Feinberg4,637,087Jan. 20, 19872.Conrad4,733,427Mar. 29, 19883.Addona, Sr.4,742,592May 10, 19884.O'Callaghan4,783,868Nov. 15, 19885.Harrell4,962,558Oct. 16, 19906.Bean5,487,397Jan. 30, 19967.Landsman5,864,917Feb. 2, 19998.Meshulam5,983,431Nov. 16, 19999.Morse6,301,737 B1Oct. 16, 200110.Fortier6,668,413 B2Dec. 30, 2003Characteristically, these prior art solutions have resulted in very inefficient force-producing schemes.Review by Patent Number
Feiberg (U.S. Pat. No. 4,637,087) discloses a fixed water foil that has a rubber surface acting like a check valve. The foil angle is fixed. The foil only provides force when pushed, but not when pulled. A plurality of apertures is blocked by check valves so as to reduce the contact pressure on the return stroke.
Conrad (U.S. Pat. No. 4,733,427) discloses a hinged hydrofoil attached to a brush. The hydrofoil provides a down force when the brush is pushed and pivots in line with the pole when pulled. The angle of the hydrofoil is fixed. The hydrofoil is designed not to contact the surface when pulled. Addona, Sr. (U.S. Pat. No. 4,742,592) discloses the use of an attachment to a pool brush comprising a plate and special mounting hardware which assists in urging the bristles of the brush against the side wall while the brush is moved in an up and down motion. A portion of the energy exerted in this up and down motion is converted by this attachment to a force urging the bristles of the brush against the side wall. O'Callaghan (U.S. Pat. No. 4,783,868) discloses a free-rotating vane for an under liquid cleaning device. The vane pivots back and forth depending on the direction that the brush is pushed. Stops limit the angle that the plate can be positioned. In O'Callaghan, the stops are not adjustable. In addition, the vane contains holes that are merely made during the construction of the hinge. O'Callahan's holes are not constructed (i.e., sized, located or angled) for control of steering. Harrell, (U.S. Pat. No. 962,558) discloses a device for cleaning a submerged surface at a distance. The invention includes a pole, a tool attachment, a pivoting hydrofoil member for forcing said tool against said surface by providing hydrodynamic force and a jetting means for directing said fluid towards said surface when the tool is moved towards the operator. It includes a pole, a brush attachment, a hydrofoil member hingedly attached to the device and a jetting means. Bean (U.S. Pat. No. 5,487,397) discloses an attachment for use on a pool brush having hydrofoil with notch and resilient clip for mounting on the brush pole. The hydrofoil can pivot to apply contact force in either direction. Landsman (U.S. Pat. No. 5,864,917) discloses a vane pivotally held on either the brush head or the elongated handle of a brush pole. Each of the vanes pivots about an axis which is normal to the direction of motion when switching between upward and downward strokes. In particular, the vanes re-position to provide contact force during the retrieval stroke. Meschulam (U.S. Pat. No. 5,983,431) discloses an attachment for a pool brush having a hydrofoil with an upstanding fin fixedly connected to a base portion at approximately a right angle thereto Flow apertures along the upstanding fin operate together with the angular configuration of the upstanding fin and base portion to produce a transverse force when the pool brush is pushed in a downward motion. Morse (U.S. Pat. No. 6,301,737 B1) discloses a unique design in that there is no hydrofoil but rather a C-shaped scoop intended to allow foreign matter to escape from the edges of the scoop in the forward stroke while minimizing impedance during the retrieval stroke. Fortier (U.S. Pat. No. 6,668,413 B2) discloses a pool brush guide that utilizes a large hinged surface with adjustable stops to directly impede and redirect fluid flow for producing a transverse force. A last example exists in the form of the “Wall Whales®” (patent Pending) presently available on the market. The Wall Whale is a brush with essentially a large flat plate with a slight curve on the trailing edge. It uses an adjustable block between the plate and the pole for setting the angle of the plate with respect to the pole. Moving the block closer to the brush increases the angle. The plate is hinged at the backplane of the brush to allow rotation. There is no captive mechanism to hold the plate in place. Literature contained in the package makes the following claims:    1. “With the Wall Whale you simply push down with one hand and the force of the water against the Wall Whale does the work. As the Wall Whale moves through the water, it pushes against the pool surface with more than 10 times the force.” (The picture shows the Wall Whale in use on the bottom of the pool.)    2. “Effortless flipping action eliminates drag on the upstroke and lifts the brush off the wall.” (The picture shows the Wall Whale in use on the side of the pool)    3. “Brush your pool in about five minutes.”    4. “Brush your pool thoroughly the first time using only one hand.”    5. “Brushing the pool without the Wall Whale is strenuous and risks injury.”
Actual use and analysis of this product has revealed the following:    1. It is impossible to use this product with one hand except momentarily. It requires two hands to position the Wall Whale on either the bottom or side of the pool and only then with some difficulty. The large hinged plate catches a lot of water and swings uncontrollably causing the user to exert additional effort to force it into position. Once there one hand can be used for the pushing stroke. But again there is a disadvantage. In order to generate ten times the force as claimed, the plate must be adjusted to a very high angle which causes an immense amount of drag. The sensation to the user is one of pushing a large bag of sand across the pool surface.    2. Drag is reduced by flipping action but the brush “flys” some distance away form the pool surface again causing the use of two hands to force the brush back into position.    3. Several attempts were made to brush a sixteen by thirty-two foot pool in five minutes. (The average size swimming pool is eighteen by thirty-six feet—Google) In five minute the walls were about two-thirds done. The bottom was never attempted.    4. Brushing the pool with the Wall Whale was strenuous due to the size of the plate and the fact that it is freely hinged and not controllable by the user.